Stuffing box and method for packing the same



April 3, 1934. r J, F, MGKEE 1,953,493

STUFFING BOX AND METHOD FOR PACKING THE SAME Filed Dec. 24, 1930 2 Sheets-Sheet l a ,1 Z F 1" April 3, 1934. J. F. McKEE 1 1,953,493

STUFFING BOX AND METHOD FOR PACKING THE SAME Filed Dec, 24, 1930 2 Sheets-Sheet 2 Patented Apr. 3, 1934 STUFFIN G BOX AND METHOD FOR PACKING THE SAME John F. McKee, Lansdowne, Pa, assignor to Yarnall-Waring Company, Philadelphia, Pa., a corporation of Pennsylvania Application December 24, 1930, Serial No. 504,606

19 Claims.

My invention relates to stufiing boxes and packings thereof.

A purpose of my invention is to add prepared charges of packing periodically bymeans of a high pressure gun.

A further purpose is to provide for the insertion of packing into a stufiing box without any material unbalancing of inwardly directed pressure exerted, by the packing upon opposite sides of the interior movable member.

' A further purpose is to build a stuffing box with packing inlets upon opposite sides ofthe box, preferably for the length of the interior thereof, and to balance the pressures exerted inwardly by the packing on opposite sides of the interior movable member.

A further purpose is to provide a stufling box with a feed box adapted to feed packing tangentially intothe stufiing box along substantially 20 the full length of the annular space thereof.

A further purpose is to form a stuffing box inlet so as to permit free movement of packing within the box in one circumferential direction only during a high pressure charging of the packing, preventing the packing from moving in the reverse direction.

A further purpose is to construct astuffing box with a preferably stationary removable cover ring.

A further purpose is to employ a fibrous material and graphite, with or without oil, as a semifluid packing.

A'further purpose is to mount screw guns permanently upon opposite sides of a stuffing box for charging high pressure packing into opposite sides of the box. Y A further purpose is to use a screw charging gun forthe removal of packing that has become dead by reason of long service, cleaning out the old packing without separating the telescoping -members of the stuffing box by loosening and sliding back a cover ring and then forcing fresh packing in bymeans of the gun, thereby starting the old packing so that it may be picked out through the open end of the box in the usual way.

Further purposeswill appear in the specification and in the claims.

I have elected to show several different forms of my invention, selecting however forms that are practical and efiicient inoperation and which well illustrate the principles involved.

Figure 1 is a transverse section through a stufling box embodying adesirable form of my invention, similar guns at top and bottom respectively of the stuffing box being shown in side elevation and section respectively.

Figure 1a is a fragmentary section corresponding generally to Figure 1, but showing a variation.

Figure 1b is a reduced diagrammatic sectional Figure 3 illustrating in section one form of a removable screw charging gun for use successively at difierent joints.

Figures 6 and 7 are fragmentary detail sections to reduced scale, illustrating different forms.

Like numerals refer to like parts in all figures. Describing in illustration and not in limitation and referring to the drawings:---

My invention is applicable to any type of stuffing box in which surfaces meet producing akiunc- .tion which must be packed, whether it be internal or external, and, if external, whether the movable member be rotating or reciprocating.

I consider that my invention may be desirably.

applied to packings for shafts, piston rods, slides,

pipes, etc., and even, a1though perhaps less advantageously, to packings for stationary parts, such as casings, where it is preferable that the parts be fully in registry before the packing is.

applied.

In spite of the general applicability .of my invention, I believe thatit has its widest use in stuiling boxes for expansion joints, particularly because of the inaccessible places in which they arefrequently located, such as in pipe line conduits. I therefore illustrate throughout the drawings stuffing boxes which are suitable for expansion joints, and I describe them with particular reference to expansion joints, although many of the principles are applicable to stumng boxes wherever found.

The joints of the illustrated type are for use" principally in pipe lines subject to wide thermal changes, as lines carrying high pressure steam or other'hot fluid. The joint includes inner and outer slide members, with the inner slidemember within longitudinally spaced cylindrical guides that are carried by the outer slide from opposite ends of a stufilng box space intermediate the guides, a major portion of the guide from the inner end of the stufling box being desirably spaced radially inwardly from the inside of the outer slide member so as to be externally jacketed by the hot fluid within the line.v

As illustrated, the telescoping inner and outer slides 10 and 11 in all of the forms of joint present their end flanges 12 and 13 for connection to the flanges of line piping, not shown.

The inner slide 10 is externally cylindrical throughout its length except for the flange 12 at one end and projections 14, desirably studs, at the other, that function to prevent inadvertent separation of the slides, as in the event-of any failure of an anchor normally preventing longitudinal opening movement. of the joint members.

The outer slide makes a close sliding fit at its overlapping end 15 with the outside of the inner slide and provides an annular stufling box space or packing cavity for packing 16 inwardly adjacent the close fitting portion at 15. Inwardly beyond the stuffing box, the outer slide carries a cylindrical guide 17, which is preferably for a considerable portion of its length spaced inwardly at 18 from the main body 19 of the outer slide to which it is connected at 20 adjacent the inner end of the stufiing box.

An embodiment of a preferred form of my invention is shown in Figures 1 and 2, where the outer slide carries packing feed boxes 21 and 22 on diametrically opposite sides of the stuffing box.

The feed box outlets 23 into the annular stuifing box 16 are al ke, each including a curving passage of preferably substantially the length and sectional area of the annulus interior of the stuffing box, the passage being formed for delivering the packing along an easy curve into circumferential movement along the stufiing box, without materially changing the sectional area of the flow or abruptly changing the path of travel, the flow entering the stuffing box substantially tangentially along the full'length and area thereof.

I preferably mount a screw gun 24 permanently at each of the; diametrically opposite feed boxes, using the guns to force an adequately fiuid packing into the feed boxes whence it discharges along the ports 23 with an easy curve into the stufling box for the full length and sectional area tl reof, each feed box supplying packing to one half only of the stuffing box.

[The charging guns 24 are shown alike, each including coaxial transversely directed cylinders 25 and 26 that extend from opposite sides of the feed box, and respectively carry screw pistons 2'7 and 28 respectively for use in charging fresh packing into the feed box from the charging cylinder 25 and for closing the feed box from connection with the charging cylinder in order to permit an easy recharging of fresh packing into the cylinder 25 without interrupting a continuous full pressure within the joint.

The inwardly directed ends of the cooperating piston heads 27 and 28 are desirably adapted to nest together, a conical recess 29 in the inner end of the charging piston being adapted to receive a conical projection 30 on the head of .the valvepiston.

This con cal interfitting is particularly desirable when the charging packing includes a strong fibrous solid, usually asbestos, suitably lubricated, as for example, by graphite and oil.

The pointed end of the valve piston forces its way between the asbestos fibers, expelling the packing as a homogeneous mixture while the solid fibers would catch between the ends of the opposing pistons if the facng ends thereof were flat.

. Obviously I may replace the permanently connected chargingpumps of Figures 1 and 2 by a non-permanent pump as shown in Figure 5, connected when needed for example through the cylinder caps 33 after the removal of the charging pistons illustrated in the figures.

The plug valve includes a stem 31 that threads through the end of the cylinder 26 and presents a square head 32 to a suitable operating wrench. The piston head 28 may desirably make a drive fit with the end of the stem 31.

The outer end of the pump cylinder 25 is normally closed by ascrew cap 33, the piston stem threading through the cap which is removable to permit recharging the pump cylinder with fresh packing.

I find the packing may suitably comprise a mixture of graphite, high grade heavy petroleum oil and a fibrous solid desirably asbestos. A shredded bearing metal, such as lead, could also be used.

This packing may be substantially non-fluid at ordinary pressures but I find that under the high pressure exerted by thescrew pistons of the any point of the solid fibers of the packing, as

any catching of the fibers usually develops a greater or lesser damming of the passage, separation of the solid and fluid constituents of the packing and abnormally high and low inward pressured within the passage on opposite sides respectively of the dam.

To secure an easy curving entry of the packing into the stuffing box I extend the rearward wall 34 of the inlet port 23 across a considerable portion of the radial depth of the stuffing box, curving it forwardly to secure a substantially tangential entry of the packing into the box.

The separating Wall guiding lip 34 extends the full axial length of the stuffing box and its forward curving prevents the packing from being forced squarely inwardly against the circumferential surface of the inner pipe, the packing moving substantially tangentially to the inner pipe when it first engages this pipe, thereby avoiding any excessively heavy radially inward pressure along the line of first engagement between the inner pipe and the packing when the packing enters the stuffing box.

The inwardly extending walls or lips 34 form on their forward side a curving guiding wall for charging packing and on the rearward side act as a dam limiting the forward travel of packing charging from the opposite inlet. To secure proper entry of the packing into the space beneath these walls I provide them with undulating, corrugating or saw-tooth contours along their inward edges as best seen in Figures 1 and 2.

The portions 35 that extend furthest inwardly prevent the fiber portions of the packing from working backwardly while the recesses 36 permit a more complete filling of the space beneath the lip, this filling taking place principally from packing that has been forced in through the opposite inlet.

While the packing will flow under the high pressure that may be exerted by the screw pump, I find the packing, because of its fibrous char- 'acter and high viscosity, only very imperfectly obeys fluid laws, the inward presure exerted by the packing upon the surface of the interior pipe having initially a heavy downward gradient from the point of entry at the forward side of one lip 34 circumferentially along the stufling box to the rearward side of the other lip, the inward pressureexerted by the packing being progressively greater in moving from any point rearwardly toward the line of the packing inlet.

I find that unless the packing is exceptionally fiuid or the stumng box diameter is quite small, theinward pressure of the packing upon the inner pipe, when the packing is inserted all along one side only of the stufiing box, is thus unbalanced, being much heavier on the side near the inlet than diametrically opposite thereto, the unbalance of pressure forcing the joint members together upon one side to an extent that prevents the relatively easy sliding movement between the members that is essential to proper operation of thejoint and which I find is readily obtained if the inward pressures of the packing upon opposite sides of the inner pipe are in substantial balance. 25

In the forms of Figures 1 and 2 the pressure gradient is downward from the opposite inlets to the rearward sides of the lips 34, but the same pump pressures being applied at one inlet as at the other inlet, a relatively high opposing inward pressure near the other inlet, and progressively lower inward pressures at points progressively further from the one inlet are respectively balanced by corresponding progressively lower pressures at diametrically opposite points of the box.

I usually much prefer to provide inlet ports 23 alongthe full axial length of the annular interior of the stuffing box, as illustrated in Figures 1 and 2.

This requires a constant length for the stuffing box and therefore a non-adjustment of the position of the member 15 closing the forward end of the stumng box.

In Figures 1 and 2 this includes a 'ring 15 removably fastened by suitable bolts 37 to lugs 38 on the outer pipe member. -The outer end of the outer pipe fits in a suitable groove 39 of the ring, packing 40 being shown to effect a seal between the ring and outer pipe member.

I desirably provide the ends of the box with tightly fitting rings 41 and 42 when the joint is assembled, the length of the box being suitably increased by the thickness of these rings beyond the length of the inlets from the feed box so that the packing is substantially the same as the the need for doing this varying with the size of the joint, the sectional area of the stuffing box annulus and the character of the packing.

It will be understood that there will be less variation in the inward pressure exerted bythe packing al'ong circumferentially different parts of the stufling box upon the inner pipe the greater the radial depth of the stuffing box interior, the

more fiuid the packing and the less the longitudinalwdistance t hat has to be charged by a single inlet port.

Although I consider that the tangential form of inlet is much preferable to any other form, particularly for a viscous packing, I find that a plurality of radial inlets maybe used with part of the advantage ofmy invention, particularly when the packing is very fluid. In Figure 10, I show a stufling box corresponding generally to that of Figure l, but having radial inlets 23' at a plurality of spaced points. This form will preferably be used with very fluid packing. The inlets need not be strictly tangential in order to gain part of the advantage of tangential inlets. In Figure lb I show inlets 23 directed against the inner movable member at an angle intermediate between that of the radius and that of the tangent.

It will of course be evident that the pressure for a'plurality of inlets on the'same stufiing box or on different stufiing boxes may be obtained from a common pump. In Figure 1b I show a pump 24 connected to the inlets 23 by a common passage 24 g The form of Figure 1b has the advantage that the pressures at the various inlets will bear a fixed relation to one. another, and, if the packing be sufiiciently fluid, will be equal. 1 Where the joints are of relatively small diameter, the radial depth of the stuffing box rel ativelylarge, or the character of packing relatively fluid, the type of joint illustrated. in Figures 3 to 5 may at times be preferable to that of Figures 1 and 2 in that'it is less expensive to manufacture and with manyplant conditions will adequately perform the intended service.

The feed boxes of Figures 1 and 2 have been dispensed with, the inlet port preferably placed near the inner. end of the stufling box entering tangentially and being provided with a plug valve 43 in order to permit removal of a charging gun 44 after the gun has been used to charge the box.

In the form of Figures, 1 and 2 and also in that of Figures 3 to 5 the ring 15 at the end of the fastened to the outer pipe.

An advantage in making the ring non-adjustable longitudinally of'the jointlies' in the fact that the length of the interior of the stufiing box is then constant and in the further fact that any movement of the ring would upset the sectional registry of the stuffing box with the inlet from the feed box, length registry being possible for one position only of the ring.

The advantagein havingthis ring removable lies in the fact that its removal from the end of the outer pipe and sliding back along the inner pipe permits an easy cleaning out of old packing within the joint.

At long intervals, each including perhaps a number of years of service, thexpacking may have deteriorated or become dead to an extent making it desirable to wholly replace the old packing with fresh packing and I may do this without taking down the piping by removing the retaining nuts 45 or bolts 45', sliding back the ring 15, loosening the old packing within the box by forcing in fresh packing at the charging pumps, and then picking out the loosened old packing from the open end by means of 'asuitable tool; the use of the charging pumps to first start the dead packing being a very great aid in its ultimate removal by the picking tool.

When circumstances or conditions are such as to make it improbable that the packing will ever have to be removed; I mayprefer to use the feed box in order to permit opening and re-;

form illustrated in Figure 6 where the ring 15 forms-a permanent part of the outer slide memher.

A charge of packing after a period of long service may become inadequate for a perfect seal, due no doubt to the relative movements during service of the inner and outer slides, so that after continued service of perhaps a year or more, it may be desirable to add charges of fresh packing.

In the form of Figures 1 and 2 Ido this by means of the charging pumps on opposite sides of the joint, perhaps merely tightening the screw pistons of the pump members to deliver suitable quantities out of the pump cylinders and refilling the cylinders of these pumps as needed.

In the form of Figures 8 to 5, a singlegun 44 may be used successively at any desired number of the joints, adding the make up charges for example, at regular periodic intervals to perhaps many different joints about a large plant.

I may, as indicated in Figure 7, make the ring 15 at the end of the stuffing box a gland adapted to be tightened at periodic intervals in order to suitably compress the packing within the box.

While in some cases this may be preferable, particularly with the form of tangential inlet shown in Figure 3 to 5, it is perhaps less desirable with the form of Figures 1 and 2 in that changing the position of the end of the gland will change the length of the stufiing box and therebyupset the sectional registry between the inlet ports and the stuffing box.

Another disadvantage of using the closure ring 15 as an adjustable gland lies in a resultant variation in the length of guiding connection between the inner and outer slides, which may be important if the joint is 'to have a minimum length consistent with efficient operation.

The pumping into a stufling box of a mixture of asbestos or other fibrous material and graphite, of asbestos, graphite and an oil, or of a bearing metal andan oil, as a semifiuid or plastic packing, as distinguished from inserting a preformed packing is part of my invention.

It will be seen that in all of the different illustrations I show my substantially tangential inlet into a stufiing box for supplying the box with adequate fluid packing; that in Figures 1 and 2 I provide a feed box having tangential inlet for the full length of the stuffing box; also that I provide tangential inlets upon diametrically opposite sides of the joint, thereby securing a balance of the inward pressure of the packing upon the inner pipe after it has been charged by the guns.

It will be seenthat I also mount the cylinders of the charging guns as integral portions of the outer slide member withplug valves in position to close the connection between the cylinders and charging the cylinders with fresh packing without disturbing the continuous service of the joint.

In the forms of Figures 1 to 5 I have made the closure of the stufiing box at the outer end thereof adapted to.be moved from the stufiing box outwardly along the inner pipe, which permits the use of the charging guns for starting dead packing with subsequent easy cleaning out of the open end of the stufiing boxes. In Figure 6 I illustrate that where this feature is not needed the end of the box may desirably be made integral' with the outer pipe.

It will be evident that the above features are applicable to any type of stufling box, no matter what its character or how the parts may move.

In view of 'my invention and disclosure variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of my invention without copying the structure shown, and I, therefore, claim all such in so far as they fall within the reasonable spirit and scope of my invention.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:-

1. A stufiing box having meeting surfaces producing an annular junction to be packed, walls forming a packing cavity of uniform annular cross section communicating with the junction, an inlet to the packing cavity, and a partition wall extending abruptly toward the interior of the annulus, partially separating angularly adjacent portions of the packing cavity and adapted to permit flow in one circumferential direction only while giving maximum space for packing.

2. A stuffing box having meeting surfaces producing an annular junction to be packed, walls forming a packing cavity of uniform annular cross section communicating with the junction, a plurality 'of inlets to the. packing cavity and a plurality of partition walls each extending abruptly toward the interior of the annulus, partially across the cavity and respectively adjacent the said inlets to permit fiow in one circumferential direction only while giving maximum space for packing on both sides of each partition wall.

3. In a stuifing box having meeting surfaces producing a junction to be packed, walls forming apacking cavity communicating with the junction, aplurality of inlets to the packing cavity and a plurality of partition walls adjacent the respective inlets partially separating portions of the packing cavity and having saw-tooth exposed ends.

4. In a stuffing box joint for moving parts, a stuffing box surrounding the movable member and providing a space therebetween, an inlet therefrom giving direction to the packing substantially parallel with the movable surface, means for exerting high pressure upon the packing and a supplemental closure separate from the pressure means'for shutting off the pressure after it has been raised, and for maintaining the pressure, the supplemental closure comprising a longitudinally movable plunger.

5. In an expansion joint of the character in dicated, an inner slide, an outer slide telescoping therewith, a packing box near the overlapping end of the outer slide and inlet passages into the box on substantially opposite sides thereof for high pressurefiuid packing, the interiors of the passages having lips projecting in the direction of fiow 'and making a curving substantial registry With the annulus interior of the box, the packing having at the point of discharge to the inner slide unidirectional movement substantially tangent to the surface. 4

6. In an expansion joint of the character indicated, an inner slide, an outer slide telescoping therewith and having a packing box near its overlapping end for relatively sealing the inner and outer slides, a feed box mounted on the packing box and opening into the annulus thereof along a considerable portion of the length thereof, a pump cylinder opening into one side of the feed box, a plug valve including a valve element within the feed box at said cylinder opening, a

pointed end directed axially into the opening and an operating stem threading the opposite wall of the feed box, a piston within the cylinder axiallyrecessed to adapt it to nest with the pointed end of the valve, a cap removably mounted on the outer end of the cylinder and a piston stem threading through the cap for operating the pump.

7. An expansion joint, a stuffing box communicating with the joint, means for forcing packing into the stufiing box and a valve between the said means and the stufiing box comprising axially aligned movable members having one a concave end surface and the othei' a convex end surface, adjoining each other and both adapted to be moved in the same direction to engage one with the other, the one performing the function of a valve and the other removable for admission of additional packing.

8. An expansion joint, .a stuffing box connected therewith, screw means for forcing packing into said stumng box and a valve coaxial therewith adapted to close the end of the passage through which the packing is fed to perform its valve function therewith and threaded for movement therewith, the said valve moving axially toeffect closure thereby compressing the packing prepara- I tory to efiecting closure.

9. In an expansion joint of the character indicated, an inner slide, an outer slide telescoping therewith and having a packing box near its overlapping end for relatively sealing the'inner and'outer slides and a valved connection into the box opening beyond the valve tangentially into the annularspace of the box along a considerable portion of the length thereof and forming an inlet for high pressure fluid packing, and said inlet connection having a guiding wall along the rearward side of the inlet passage across a' annulus for guiding theinlet packing into easy registry with the curve of the annulus, and said wall presenting corrugations toward the outside surface of the, inner slide. 1

10. In an expansion joint of the character indicated an outer slide, an inner slide telescope ing therein, walls forming an annular packing space of uniform cro'ss section between the outer and inner slides, a plurality of pumps equally circumferentially spaced around the outside of the outer slide, the pumps containing plungers,- each of which is generally tangential to the annular packing space and partition walls extending diagonally into the packing space and for the full length of the\packing space, one adjacent each pump, and directing the flow of packing unidirectionallz, around the annular packing space.

11. In a stufifing box, annular mating walls forming a junction to be packed, walls formingequally circumierentially spaced inlet ports around the packing space, a projection at one 'side of each inlet port extending into the packing space to a point adjacent the junction to be packed and, extending diagonally across the inletport, all of the projections being disposed in the same direction with respect to annular travel of packing around the annular packing space, and pump means for introducing packing through the inlet ports, whereby the flow oi packing will be unidirectional around the pack.- ing space and will be assisted by thev diagonal projections at the inlet ports.

12. A stufling box having meeting surfaces producing a junction to be packed, walls forming a packingcavity communicating with the junction, an inlet to the packing cavity having one end of its axiallength adjacent the junction, said inlet being fixed with respect to the stuffing box, a piston pump connected to the inlet and a closure for the inlet movable to a position against the face of the pump piston to first compress the packing and then close the inlet.

13. In an expansion joint, an outer slide, an inner slide telescoping therein, walls'forming an annular stufling box packing the joint between -the slides, a gland ring closing one end of the stuffing box, means for removably attaching the ring to the box, walls forming an inlet port into the stufing box, a pump in communication with the inlet port and a partition wall inside the box extending for substantially the full length of the box approximately'to the inner slide for directing packing unidirectionally around the packing space.

14. In an expansion joint, an outer slide, an inner slide telescoping therein, walls forming an annular stufling box packing the-joint between the slides, a gland ring closing one end of the stufling box, means for .removably attaching the ring to the box, walls forming a plurality of equally circumferentially spaced inlet portsinto the stufing box, a pump in communication with each inlet port and a plurality of partition walls inside-the box extending for substantially the full length of the box approximately to the inner slide and one adjacent each inlet port for directing packing unidirectionally around the packing space. v

15. In an expansion joint, an outer slide, an inner slide telescoping therein in radially spaced relation to the outer slide, an annular guide surrounding and engaging the inner slide, secured to the outer slide and spaced from the outer slide over a substantial part of the length of the guide, walls forming an annular stumng box between the guide and the telescoping end of the outer slide, the guide closing -.one end of the stumng box, a gland ring'closing the other end of the stufiing box, means for removably attaching the ring to the box, walls forming a plurality of equally circumferentially spaced inlet ports into the stuffing box, a pump in communication with each inlet port and a plurality of partition walls inside the box extending for substantially the full length of the box approximately to the inner slide and one adjacent each inlet port for directing packing unidirectionally around the packing space.

16. In an expansion joint, an outer slide, an inner slide telescoping therein, walls forming an 133] annularstufing box packing the joint between 'the slides, a gland ring closing'one end of the stuning box, means for removably attaching the ring to the box, walls forming a plurality of equallyocircumferentially spaced inlet ports into 135 the stumng box, a pump in communication with each inlet port, a screwplug valve in each inlet port" and longitudinally movable to close each inlet port and a plurality of partition walls inside the box' extending for substantially the full length of the box and one adjacent each inlet port for directing packing unidirectionally around the packing space.

17. In an expansion joint, an outer slide, an inner slide telescoping therein in radially spaced relation to the outer slide, walls forming a stuif- 'ing box or enlarged cross section at the telescoping end of the outer slide,an annular guide en-' gaging the inner slide, secured to the outer slide at one end, said end comprising the rear of the 150 stufllng box, and extending for a substantial distance in spaced relation to the outer slide, a. gland ring closing the front of the stufilng box, means for removably attaching the ring to the box, walls forming a plurality of packing inlet passages equally circumferentially spaced around the stufilng box and pumps communicating with each inlet passage.

18. In a stufilng box, walls forming an annular packing cavity, a gland closing one end of the packing cavity, means for removably attaching the gland to the stuffing box, a radial inlet to the packing cavity, a partition wall extending for the full length of the cavity adjacent the inlet and-in curving substantial registry with the inner wall of the cavity and a pump in communication with the inlet, whereby packing is introduced unidirectionally.

19. In a stufling box, walls forming an annular packing cavity, a gland closing one end of the packing cavity, means for removably attaching the gland to the stuffing box, a plurality of equally circumferentially spaced inlets to the packing cavity, a plurality of partition walls, one extending for the full length of the packing cavity adjacent each inlet and in curving substantial registry with the outer wall of the cavity, a plurality of ports, one in communication with each inlet and a plurality of longitudinally movable valves, one acting oppositely to each pump, for closing off flow of packing into the packing cavity.

JOHN F. McKEE. 

